TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhysProc.8.074
TI  - The photon content of the proton in the CT18 global analysis
PY  - 2022/07/12
UR  - https://scipost.org/SciPostPhysProc.8.074
JF  - SciPost Physics Proceedings
JA  - SciPost Phys. Proc.
VL  - 
IS  - 8
SP  - 074
A1  - Xie, Keping
AU  - Hobbs, Timothy
AU  - Hou, Tie-Jiun
AU  - Schmidt, Carl
AU  - Yan, Mengshi
AU  - Yuan, Chien-Peng
AB  - Recently, two photon PDF sets based on implementations of the LUX ansatz into the CT18 global analysis were released. In CT18lux, the photon PDF is calculated directly using the LUX master formula for all scales, $\mu$. In an alternative realization, CT18qed, the photon PDF is initialized at the starting scale, $\mu_0$, using the LUX formulation and evolved to higher scales $\mu(>\mu_0)$ with a combined QED+QCD kernel at $\mathcal{O}(\alpha),~\mathcal{O}(\alpha\alpha_s)$ and $\mathcal{O}(\alpha^2)$. In the small-$x$ region, the photon PDF uncertainty is mainly induced by the quark and gluon PDFs, through the perturbative DIS structure functions. In comparison, the large-$x$ photon uncertainty comes from various low-energy, nonperturbative contributions, including variations of the inelastic structure functions in the resonance and continuum regions, higher-twist and target-mass corrections, and elastic electromagnetic form factors of the proton. We take the production of doubly-charged Higgs pairs, $(H^{++}H^{--})$, as an example of scenarios beyond the Standard Model to illustrate the phenomenological implications of these photon PDFs at the LHC.
ER  -

@Article{10.21468/SciPostPhysProc.8.074,
	title={{The photon content of the proton in the CT18 global analysis}},
	author={Keping Xie and T. J. Hobbs and Tie-Jiun Hou and Carl Schmidt and Mengshi Yan and C. -P. Yuan},
	journal={SciPost Phys. Proc.},
	pages={074},
	year={2022},
	publisher={SciPost},
	doi={10.21468/SciPostPhysProc.8.074},
	url={https://scipost.org/10.21468/SciPostPhysProc.8.074},
}